Illumination



March 31,1942. A. MACK E 2,278,142

1 ILLUMINATION Eiled Feb. 20, 1940 Patented Mar. 31, 1942 UNITED STATES... PATENT OFFICE ILLUMINATION Alfred Mack, Mary W. Mack, and Alfred W. Mack, Framingham, Mass., assignors of one-fourth to Lawrie L. Witter, Boston, Mass.

Application February 20, 1940, Serial No. 319,916 3 Claims. r01. 240-452) This invention relates to illumination and more particularly to a dual purpose vehicle lamp adapted for use under both normal and abnormal conditions. In its preferred form the lamp embodies a clear and transparent lens having com-i 1.

bined over a portion thereof a filter for eliminating certain objectionable light waves as hereinafter described. Associated with; the main driving portion of the lens is a system of shutters arranged to be placed in either open or closed:-

position at the will of the driver. Under normal conditions, the shutters will be left open thereby permitting the entire light to pass through the lens and, under foggy or other abnormal conditions, the shutters will be closed whereby the light can pass through only the filtering portion of the lens. The production of such a dual purpose lamp comprises the primary object of the invention.

These and other features the invention will be more readily understood and appreciated from the following description of a preferred embodiment thereof selected for purposes of illustration and shown in the accompanying drawing in which:

Fig. 1 is a sectional view through a lamp illustrating the invention,

Fig. 2 is a front view thereof with a portion of the lens broken away,

I Fig. 3 is a somewhat diagrammatic view of the lamp.

Our novel lamp comprises a shell 20, a bulb and a reflector 22 and 24 and a lens 25. -The lens is clear and transparent and the upper half thereof is provided with a filter film 26 at its inner face. Cooperating with the lower half of the lens and at its inner face is a system of shutters 28 mounted to be moved to open and closed positions. Any convenient means operated either mechanically or electrically can be pro-J vided for thus moving the shutters.

As more specifically illustrated in Fig. 3, the shutters comprise a plurality of blades 28 pivoted at 30 on a relatively thin bar 32 extending vertically within the shell rearwardly of the lens, the blades being slotted at 33 to clear the bar. Ears 34 carried by the shutters have pivotal connection with a vertical bar 36. When the bar 36 is in the down position of Fig. 3 the shutters are open whereby permitting the light to pass freely through the bottom portion of the lens. Raising the bar 36 pivots the shutters downwardly to closed position whereby preventing the passage of light through the bottom portion of the lens. The shutters and cooperating elements are highly polished and relatively thin whereby to avoid interference with the projection of the light through and beyond the lens.

We have illustrated a relatively simple means for moving the shutters electrically to the seand advantages of;

lected position when turning on the light switch. One arm of a bell crank 38 pivoted at'46 is connected to the bottom end of the bar 36 and a link 42 connects the other arm to the bottom end of a lever 44 pivoted at 46. The lever 44 is grounded at 48 and a resilient contact member 56 carried at its top end is adapted to engage either of two contacts 52 and 54. Connected to the lever 44 above and below its pivot are two cores 56 and 58 of two solenoids 66 and 62. The solenoids 60 and 62 are in circuit with the contacts 52 and 54 respectively. A double pole switch pivoted and grounded at 64 is adapted in either closed position to close the circuit through the light 22 through contacts 65. The other two contacts 66 and 68 are in circuit with the solenoids 60 and 62 respectively. A spring 10 anchored at 12 and connected to the lever 44 at 14 is adapted to complete the swinging of the lever in both directions and to hold the lever in either of its two positions and the shutters in the open and closed positions.

In Fig. 3 the shutters are shown in the open position, the member 50 being in engagement with the contact 54. Closing of the switch to contacts 65 and 66 closes the light circuit and leaves the shutters in the open position. Closing of the switch to contacts 65 and 68 closes the light circuit and energizes the solenoid 62. The.

core 58 thereupon rotates the lever 44 clockwise and closes the shutters. Thus in one position of the switch the lens is fully open for ordinary driving and in the other position of the switch the shutters are closed and the light can pass only through the filtering portion 26 of the lens. The shutter operating mechanism can be conveniently housed within or adjacent to the shell 20, as indicated at 15. The lower and clear portion of the lens 25 is preferably provided with a filter film 21 to eliminate short waves of light which tend to bounce and have a tiring effect on the eyes of the driver.

The specific character of the filtering portion of the lens will depend upon the function to be performed. The lamp is adapted to uses requiring relatively normal and abnormal illumination. One of the most common of such uses is on motor vehicles wherein normal driving illumination is required in clear weather and filtered driving illumination is required under foggy or like atmospheric conditions. The filter film which we preferably employ for this purpose is applied directly to the rear face of the lens, the preferred filter material being a highly transparent and waterproof coloring dye brushed or otherwise applied directly to the lens to form a thin film thereover. We have found that thefilter as thus formed affords a maximum of light trans- :mission and filtering efliciency due both to the extreme thinness of the film. The dye which we have used and found highly eflicient for the purpose of this invention is manufactured and sold by McGill Manufacturing Company, Valparaiso, Indiana, and is called Crescent lamp dye, this dye being most commonly used to color the outside of incandescent lamp bulbs. The dye is water-proof, highly transparent, and resistive of such heat as is developed by incandescent lamps.

The projecting of the light in a color corresponding to the longest possible wave length of the spectrum which it is practicable to use is effected by using a dye of a red tinted shade or color produced by so tinting amber with red as to produce a reddish or goldentinted amber color which transmits light on a wave length closely approaching the red band of the spec- The proportions which we have found most suitable have approximated the addition of three to four drops of Crescent red lamp dye to ten cubic centimeters of Crescent amber lamp dye.

A filter film 26 of such a red tinted shade orcolor eliminates the short and highly refractive light waves while the longer and more powerful rays pass through the filter and lens without appreciable change or loss. These strong and desirable rays project forwardly and penetrate a substantial distance with powerful and effective illumination. It is also important that the refractive index of these waves are at the lowest possible minimum whereby the objectionable refraction heretofore present is substantially reduced and the light beams are correspondingly more able to penetrate through foggy or like atmospheres. These features together with the fact that the light is projected in a color .corresponding to the longest possible wave length of the spectrum which it is practicable .to use produces a light with maximum penetrating and illuminating powers.

While we have above more particularly illustrated and described the invention in its -appl-i-' cation to the penetrating of fog or the like, we desire it to be understood that other and valuable applications to very important uses are possible within the broad scope of the invention. For example, it is possible, by using a dye of a blue shade in forming the filter, to eliminate the long and powerful light rays at the red end of the spectrum whereby permitting onlythe short and relatively weaker rays to project beyond the lens. These rays can be used for purposes of visibility at relatively short ranges but, since they do not have the power and carrying capacity of the longer rays, they do not provide visibility from any substantial distance. Such lighting effect is highly useful, for example. where it is desired to escape detection from a distance, as in military operations. Pedestrians and other objects on the ground thus illuminated can be observed at relatively close range but tial distance. This effect is due to the fact that these short wave rays are relatively weak and have little penetrating power. The volume of illumination thus effected can be very definitely controlled by the filter color or shade used and the effect can be made such that detection from the air at any reasonably safe distance is substantially impossible. Our lamp constructed to project filtered illumination of this nature and for this purpose will also have a substantially clear main driving portion adapted to project such full driving illumination as conditions not requiring the filtered illumination warrant or permit, and the uses can be optionally employed at the will of the operator.

Having thus described our invention what we claim as new and desire to secure by Letters Patent of the United States is:

l. A dual purpose lamp, comprising a shell, a lens having a light filtering portion for emergency driving and a substantially clear driving portion, a reflector within the shell rearwardly of the lens, means providing a source of light between the reflector and lens, shutters associated with the driving portion of the lens and arranged to present an open position permitting the passage of light rays and a closed position preventing such passage, and means for opening and closing the shutters, the lamp being adapted to project only filtered illumination through the filtering portion of the lens when the shutters are closed and to project full illumination through the clear portion of the lens when the shutters are open.

2. A dual purpose lamp, comprising a shell, a transparent lens, a reflector within the shell rearwardly of the lens, means providing a source of light between the reflector and lens, a filter film associated with a portion of one face of the lens and of a color to filter out the short waves of light at one end of the spectrum, pivotally mounted shutters associated with a remaining portion of the lens and arranged to present an open position permitting the passage of light rays and a closed position preventing such passage, means for pivoting the shutters to open and closed positions, and means remote from the shell for controlling the operation of the first named means, the lamp being adapted to project only filtered illumination through the filter film portion of the lens when the shutters are closed and to project full illumination through the remaining portion of the lens when the shutters are open.

3. A dual purpose lamp, comprising a shell, a transparent lens, a reflector within the shell rearwardly of the lens, means providing a source of the lens and of a color to filter out certain would be invisible from the air at any SUbStQH-r waves of light at one end of the spectrum, shutters associated with a remaining portion of the lens and arranged to present an open position permitting the passage of light rays and a closed position preventing such passage, and means for opening and closing the shutters, the lamp being adapted to project only filtered illumination through the filter film portion of the lens when the shutters are closed and to project full illumination through the remaining portion of the lens when the shutters are open.

ALFRED MACK.

MARY W. MACK.

ALFRED W. MACK. 

